The present invention relates to a cartridge for the preparation of whipped beverages and, in particular, to sealed cartridges which are formed from substantially air- and water-impermeable materials and which contain one or more ingredients for the preparation of beverages.
It has previously been proposed to seal beverage preparation ingredients in individual air-impermeable packages. For example, cartridges or capsules containing compacted ground coffee are known for use in certain coffee making machines which are generally termed xe2x80x9cespressoxe2x80x9d machines. In the production of coffee using these coffee machines the coffee cartridge is placed in a brewing chamber and hot water is generally caused to pass under pressure through the cartridge, thereby extracting the aromatic coffee constituents from the ground coffee and producing a coffee beverage. Typically in the production of xe2x80x9cespressoxe2x80x9d coffee a brewing time of about 25 seconds is used at a pressure of about 6xc3x97105 Pa, or greater.
Cartridges containing roast and ground coffee in which hot water flows under gravimetric force through the cartridge are also known. A cartridge of this general type is described in British Patent No. 1397116.
In EP-A-0272922 there is described a package which contains at least one beverage preparation ingredient, e.g. roast and ground coffee. In a preferred embodiment the package is formed from a substantially air- and water-impermeable material and comprises a sealed body portion having a compartment containing the beverage ingredient and an outlet channel, the compartment and the outlet channel cooperating in such a manner that, in use, the beverage is filtered, thereby avoiding the necessity for an external filter.
There is also described in EP-A-0272922 a method for preparing a beverage which comprises positioning the beverage containing package at a brewing station, introducing water through water introduction means into the package, allowing the water to commingle with the beverage ingredient, and collecting the beverage so-formed through an outlet formed in the package.
The beverage packages as described in EP-A-0272922 are primarily intended to be used with a beverage preparation machine which handles the packages automatically or semi-automatically. A machine of this type is described in EP-A-0334572. The packages may contain roast and ground coffee, leaf tea or one or more powdered beverage preparation ingredients such as powdered chocolate, powdered coffee or powdered soup.
The machines described in EP-A-0272922 operate at a relatively low pressure of less than 2xc3x97105 Pa and thus, although by varying the amount of water introduced into packages containing roast and ground coffee it is possible to obtain a coffee beverage of the same strength as xe2x80x9cespressoxe2x80x9d coffee, it is not possible to incorporate gases into the coffee beverage at this pressure to provide the beverage with the foamed texture and appearance of xe2x80x9cespressoxe2x80x9d coffee.
EP-A-0638486 describes a cartridge operating at relatively low pressure which is capable of producing whipped beverages. The cartridge contains one or more beverage ingredients and comprises an inlet for the introduction of an aqueous medium, or compartment containing the one or more beverage ingredients, an outlet for the beverage produced from the beverage ingredient(s) and whipping means provided in the path of the beverage prior to the outlet to whip the said beverage. The whipping means generally comprises an impeller which is adapted to engage an external driving device on the beverage preparation machine, for example a machine of the type as described in EP-A-0334573.
Although an xe2x80x9cespressoxe2x80x9d coffee is produced using the cartridge and method as described in EP-A-0638486, this solution requires the modification of the beverage preparation machine as described in EP-A-0334573, which is expensive. There still therefore remains a requirement for a suitable means to produce an xe2x80x9cespressoxe2x80x9d coffee in a simple and effective manner at a relatively low pressure, e.g. of up to 2xc3x97105 Pa.
Accordingly, the present invention provides a cartridge containing one or more beverage ingredients and being formed from substantially air- and water-impermeable materials, the said cartridge comprising an inlet for the introduction of an aqueous medium into the cartridge, a compartment containing the beverage ingredient or ingredients and an outlet for the beverage produced from the beverage ingredients, characterized in that the cartridge incorporates in the beverage flow path, prior to or at the outlet, means for producing a jet of the beverage, at least one inlet for air and means to generate a pressure reduction of the jet of beverage, whereby in use air from the at least one air inlet is incorporated into the beverage as a plurality of small bubbles.
It will be understood that by the term xe2x80x9ccartridgexe2x80x9d as used herein is meant any package, sachet or receptacle which contains one or more beverage ingredients and from which a beverage may be produced.
In use, the cartridge of the present invention will have water under pressure passed therethrough. Generally the pressure within the compartment containing the beverage ingredients will be in the range of from 0.7 to 2.0xc3x97105 Pa.
The means to produce a jet of the beverage generally comprises a restriction in the flow path of the beverage, preferably at least one restriction hole or nozzle.
It will be understood that a plurality of jets may be produced, in which case a plurality of restrictions would be incorporated into the beverage flow path, for example a plurality of restriction holes or nozzles.
The cross-sectional area of the restriction hole(s) or nozzle(s) will generally be chosen to give a flow rate of the jet of beverage of from 3 to 20 metres per second, preferably 8 to 16 metres per second and more preferably about 10 metres per second. Typical cross-sectional areas are in the range of from 0.3 mm2 to 0.8 mm2.
The means to generate a pressure reduction of the beverage will generally comprise a chamber or conduit opening which allows expansion and mixing of the beverage to occur.
At least one air inlet is provided. The air inlet(s) will generally comprise one or more narrow passages which connect from the outside of the cartridge which is at atmospheric pressure to the chamber or conduit opening where the pressure reduction of the beverage occurs. Preferably, the air inlet is positioned as close as possible to the restriction hole or nozzle.
In one embodiment of the invention, a surface is incorporated into the beverage flow path, between the means for producing the jet of beverage and the outlet, onto which the jet of the beverage impinges. The angle between the path of the jet of beverage and the surface onto which it impinges is preferably at an included angle of 20 to 50 degrees, more preferably from 25 to 35 degrees. The surface onto which the jet of beverage impinges may, if desired, be textured, for example the surface may comprise a plurality of ribs, grooves or projections.
In another embodiment of the invention, the jet of beverage with air entrained from the air inlet, is passed to a mixing tube where the two phase mixture expands to fill the mixing tube and air bubbles are formed therein.
The cartridge of the present invention preferably has a body portion which may be formed, for example, from a moulded plastics material such as polypropylene. The inlet and/or outlet of the cartridge may be closed by a plug of a plastics material moulded into the inlet and/or outlet nozzle during the moulding of the body portion. Alternatively, the inlet and/or outlet may be covered by a substantially air- and water-impermeable material, for example aluminium foil or a laminated material, such as a laminate of plastic material/metal foil/plastic material prior to the opening of the inlet and/or outlet. Specific examples of materials which may be used are aluminium foil having a thickness in the range of from 30 to 60 micrometres coated with a layer of polypropylene or a laminate of polypropylene/aluminium foil/polyester.
The outlet in the cartridge may be prepared during the beverage preparation cycle using a cutting and piercing tool for example of the type as described in our EP-A-0334573.
Alternatively, the inlet and/or outlet may be open and the cartridge provided with an outer wrapping or the like. For example, a plurality of packages may be provided with a shrink wrapped outer layer.
In the cartridge of the present invention, the communication between the inlet and the compartment containing the beverage preparation ingredient(s) is preferably via a channel which is separated from the compartment by a wall which has a plurality of openings formed therein for the entry of a liquid medium into the compartment. The channel preferably extends along at least one side of the compartment, more preferably along three sides of the compartment. The openings in the wall are preferably in the form of elongate slots which are generally arranged in a manner such that an even distribution of the liquid medium through the beverage preparation ingredients is achieved.
The cartridge of the present invention may have a filter disposed between the compartment containing the beverage ingredient(s) and at least a part of the under surface of the top of the cartridge, one or more passages being formed between the filter and the top of the cartridge, the passages communicating with the outlet. This type of cartridge is particularly preferred when the beverage ingredient is roast and ground coffee.
The filter is preferably made from a material with a high wet strength, for example a non-woven fibre material of polyester. Other materials which may be used include a water-impermeable cellulosic material, such as a cellulosic material comprising woven paper fibres. The woven paper fibres may be admixed with fibres of polypropylene, polyvinylchloride and/or polyethylene. The incorporation of these plastics materials into the cellulosic material renders the cellulosic material heat-sealable. The filter material may also be coated with a material which is activated by heat and/or pressure so that it can readily be sealed to ribs formed in the under surface of the top of the package, thereby forming one or more passages which communicate with the outlet.
The beverage preparation ingredients contained in the cartridges of the invention are preferably roast and ground coffee, powdered chocolate, and according to individual taste, powdered milk or creamer, sugar or artificial sweetener.
It will be understood that it may be convenient for the compartment containing the beverage preparation ingredients to be separated into two or more sections, for example, one section containing roast and ground coffee and another section containing powdered milk or creamer. In such an arrangement the means for the entry of the liquid medium into the separate compartments would be varied to suit the requirements for filtration or dissolution of the particular ingredients.
The cartridge of the present invention, when filled with roast and ground coffee, preferably contains from 2.5 to 10 grams of roast and ground coffee, preferably from 4.5 to 7 grams for the preparation of a single cup. However, cartridges which are intended to provide multiple servings of coffee will contain an appropriate amount of roast and ground coffee, for example, packages intended to provide say five cups of coffee will contain from 20 to 50 grams of roast and ground coffee, preferably from 25 to 30 grams. The roast and ground coffee is generally compacted when the beverage package is filled in order to aid the distribution and transport of water through the package.
The cartridges of the present invention are preferably provided with at least one recognition means whereby, in use, the cartridge is identified by the machine into which it is placed for treatment and the identification of the cartridge thereby causes it to be subjected to the correct treatment steps including the introduction of the aqueous medium into the cartridge and the activation of the whipping means.
The recognition means may comprise one or more surface features formed in the body of the cartridge. For example, the cartridge body may be provided with one or more indents, cut outs, protrusions or holes which can be identified by a mechanical sensor in the beverage preparation machine, the mechanical sensor registering the presence or absence of the indents, cut outs, protrusions or holes.
The recognition means may, alternatively, comprise a system which can be sensed by a simple optical device, for example a bar code printed onto the body of the cartridge, a pattern of through holes in the cartridge, a pattern of contrasting tones or colours printed onto the cartridge or cartridges containing different comestibles being of different colours.
The recognition means may also comprise one or more strips of a magnetic material applied to the body of the cartridge which can be read by an appropriate magnetic sensor, one or more shaped or divided areas of metal foil applied to the cartridge body which cause an inductive effect on movement of the cartridge in the machine, which inductive effect can be sensed; or one or more electrically conductive areas formed on the body of the cartridge which can be sensed electrically.
As mentioned above, the cartridge of the present invention contains one or more beverage preparation ingredients, for example, roast and ground coffee or leaf tea and sugar and/or creamer, as desired. One machine which can readily be adapted for the preparation of a beverage from the preferred cartridge of the invention which includes a recognition means is described in our EP-A-0334573. The only modification required to be made to such a beverage preparation machine is to incorporate an appropriate sensor or sensors into it, the sensor or sensors being designed to read the particular coding on the cartridge and to send a signal to the controller, which then selects the appropriate beverage preparation cycle and activates the whipping means.
The sensor may be, for example, a mechanical sensor, an optical sensor, a magnetic sensor, an electrical sensor or an inductive sensor. The machine is preferably adapted so that the cartridge is handled automatically following its insertion into the machine.
The incorporation of air into the beverage using the cartridges of the present invention produces a foamy, frothy beverage. Beverages which can be produced in this manner are, for example, whipped chocolate, cappuccino and espresso-type coffee. Preferably the incorporation of air into the beverage will result in from 5 to 35 percent by volume, more preferably 5 to 10 percent by volume, of air being incorporated into the beverage as bubbles having a bubble size preferably of below 300 micrometers, more preferably in the range of from 10 to 200 micrometers. Generally, whipped chocolate will incorporate a higher percentage of air by volume therein than whipped coffee.